Is Citi's new tax plan a poison pill in disguise?

Citigroup (C) plans to safeguard some of the tens of billions of dollars in future tax credits and deductions it's carrying on its books with a move that could also act as a "poison pill," making it harder for anyone to amass a big slice of the company's stock.

Announced yesterday, the "tax benefit preservation plan" was overshadowed by Citi's $58 billion exchange of preferred shares for common equity. But it's significant because it could serve as "a convenient way to avoid the possibility of other investors amassing a large stake in the company," wrote CreditSights analyst David Hendler in a note to clients.